correctly manage enableKeyboardHandlers flag

[#46750435]
text: delimit string elements in Arrays w/newlines

[#46753911]

Individual elements in text content defined as an
Array of strings will no longer be interpreted as
paragraphs.

Instead newlines will be used as delimiters before
passing to the MarkDown formatter.
update text content in About and text components

[#46753911]

- remove HTML used in About content
- replace with Markdown
- insert string elements: "", to make paragraphs
spelling
fix Mocha test failure with chained $.fail()

Thanks to Sam!
changing metadata.js => update expected-json fixtures

metadata.js for MD2D was changed in ef797bb42e2d

When changes occur in metadata.js normally the expected-json
fixtures need to be updated.

Test failures were thrown by the Mocha tests:

The serialized object does not match the original object used to create the MD2D mode
server/public/fonts/Font-Awesome: remove .git folder

[#46761159]

When copying resources to server/public make sure that
the .git modulars that deify the original folder as a
git submodule do not end up in server/public.

Not only does it add unnecessarily to the static distribution size
the presence of the .git folder prevents the gh-pages.rb script
from completing when it tries to add the new files to the gh-pages
branch:

$ git add .
fatal: Not a git repository: vendor/fonts/Font-Awesome/../../../../.git/modules/src/vendor/fonts/Font-Awesome

problem introduced in: 643b854d
index.html: use relative url to fonts

[#46761483]

Also fix Guardfile to correctly generate index.css
using updated Sass invocation used in Makefile.
use relative path for fontawesome-webfont request

[#46761677]

To make these requests valid for static distributions in
subdirectories and also when served through a proxy like
DataGames
clarify script/gh-pages.sh error mesg
use global flag in regex to update *all* links

[#45737301], [#46733573]
Markdown: newline needed between para and heading

[#45737301],
Bob's 7 new v24 Airbags models
add element_type parameter to atomsWithin
performance tweaks and alternate stopping condition for diffusion temp
reverting change to atom distribution in diffusion mml
gas sensor image in diffusion models
cleaning up unnecessary versions
Merge pull request #21 from concord-consortium/wip_diffusion_cleanup

Wip diffusion cleanup
Support clicking an atom in "Basic Diffusion on click" Interactive

[#44616231]